659 research outputs found

    A Correlation Information-based Spatiotemporal Network for Traffic Flow Forecasting

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    The technology of traffic flow forecasting plays an important role in intelligent transportation systems. Based on graph neural networks and attention mechanisms, most previous works utilize the transformer architecture to discover spatiotemporal dependencies and dynamic relationships. However, they have not considered correlation information among spatiotemporal sequences thoroughly. In this paper, based on the maximal information coefficient, we present two elaborate spatiotemporal representations, spatial correlation information (SCorr) and temporal correlation information (TCorr). Using SCorr, we propose a correlation information-based spatiotemporal network (CorrSTN) that includes a dynamic graph neural network component for integrating correlation information into spatial structure effectively and a multi-head attention component for modeling dynamic temporal dependencies accurately. Utilizing TCorr, we explore the correlation pattern among different periodic data to identify the most relevant data, and then design an efficient data selection scheme to further enhance model performance. The experimental results on the highway traffic flow (PEMS07 and PEMS08) and metro crowd flow (HZME inflow and outflow) datasets demonstrate that CorrSTN outperforms the state-of-the-art methods in terms of predictive performance. In particular, on the HZME (outflow) dataset, our model makes significant improvements compared with the ASTGNN model by 12.7%, 14.4% and 27.4% in the metrics of MAE, RMSE and MAPE, respectively.Comment: 19 pages, 13 figures, 5 table

    Stretchable hybrid bilayered luminescent composite based on the combination of strain-induced and triboelectrification-induced electroluminescence

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    High luminescence intensity from materials that are excited by external stimuli is highly desired. In this work, a stretchable hybrid luminescent composite (HLC) that has multiple luminescence modes is reported. The luminescence can be excited either by externally applied mechanical strain or by a moving object that slides against the HLC. When the HLC is deformed, such as being twisted or folded, the ZnS/Cu phosphor experiences mechanical strain that trigger the mechanoluminescence (ML) of the phosphors. Moreover, as the HLC slides against a contact object, the triboelectrification at the contact interface induces the electroluminescence of phosphor. Here, a series of internal and external factors were studied on how they influence the luminescent intensity. It is found that the luminescent intensity from the two modes can be superposed. The HLC material was used to fabricate a fiber-based luminescent device that can be driven by air flow. The overall luminescent intensity is enhanced by over 72% compared to that obtained solely from the ML. The HLC reported in this work has such potential applications as self-powered light sources and sensors as means of detecting dynamic motions and interactio

    Positive and Negative Regulation of FcɛRI-Mediated Signaling by the Adaptor Protein LAB/NTAL

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    Linker for activation of B cells (LAB, also called NTAL; a product of wbscr5 gene) is a newly identified transmembrane adaptor protein that is expressed in B cells, NK cells, and mast cells. Upon BCR activation, LAB is phosphorylated and interacts with Grb2. LAB is capable of rescuing thymocyte development in LAT-deficient mice. To study the in vivo function of LAB, LAB-deficient mice were generated. Although disruption of the Lab gene did not affect lymphocyte development, it caused mast cells to be hyperresponsive to stimulation via the FcɛRI, evidenced by enhanced Erk activation, calcium mobilization, degranulation, and cytokine production. These data suggested that LAB negatively regulates mast cell function. However, mast cells that lacked both linker for activation of T cells (LAT) and LAB proteins had a more severe block in FcɛRI-mediated signaling than LAT−/− mast cells, demonstrating that LAB also shares a redundant function with LAT to play a positive role in FcɛRI-mediated signaling

    Optic-Fiber Temperature Sensor

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    As an important parameter in industry, agriculture, biomedical, and aerospace, temperature possesses a significant position for the development of our society. Thus, it has become a hot point to develop novel sensors for temperature monitoring. Compared with traditional electronic sensors, optical fiber sensors break out for the compact structure, corrosion resistance, multiplex and remote sensing capability, cheap prices, and large transmission capacity. Especially the phase modulation type optical fiber sensors attract much attention for the fast and accurate measurement of the external parameters in a large dynamic measurement range. In this work, we review the optical fiber Mach-Zehnder interferometer (MZI) for temperature sensing which is widely used these years. The fundamental principles of MZI fiber sensors are proposed and discussed to further understand MZI. Different kind of structures for temperature sensing of recent years are summarized as several typical MZI categories and their advantages and disadvantages are indicated separately. Finally, we make a conclusion of the MZI temperature sensing and several methods typically to realize the MZI in practical application for the readers

    Adherence to anti-tuberculosis treatment among pulmonary tuberculosis patients: a qualitative and quantitative study

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    BACKGROUND: Tuberculosis (TB) patients have difficulty following a long-term treatment regimen. Efforts to improve treatment outcomes require better understanding of adherence as a complex behavioral issue and of the particular barriers to and facilitators of patient adherence. METHODS: This study was carried out in Jiangsu Province of China with both quantitative and qualitative approaches. For the quantitative study, 780 sputum-smear positive TB patients consecutively registered since 2006 in 13 counties (districts) were queried with a structured questionnaire. Patients who had missed 10% of their total prescribed doses of TB drugs were deemed as non-adherent. Risks for non-adherence were estimated by computing odds ratios (ORs) and their 95% confidence intervals (95% CIs) using a logistic regression model. We also invited 20 TB patients and 10 local health workers for in-depth interviews. We then used content analysis based on this qualitative study to explore factors associated with non-adherence. RESULTS: The proportion of non-adherence among 670 patients was 12.2%. Univariate analysis showed that patients, who were illiterate, divorced/widowed, lacked health insurance and were migrants, were more likely to be non-adherent. The crude ORs(95%CIs) were 2.38(1.37-4.13), 2.42(1.30-4.52), 1.89(1.07-3.32) and 1.98(1.03-3.83), respectively. The risk of non-adherence was lower among patients whose treatment was given under direct observation by village doctors or regular home visits by health workers, with ORs (95% CIs) of 0.19(0.10-0.36) and 0.23(0.10-0.51), respectively. In multivariate analysis, factors associated with non-adherence included illiteracy (OR: 2.42; 95% CI: 1.25-4.67) and direct observation by village doctors (OR: 0.23; 95% CI: 0.11-0.45). The in-depth interviews indicated that financial burdens and extra medical expenditures, adverse drug reactions, and social stigma were additional potential factors accounted for non-adherence. CONCLUSION: More importance should be given to treatment adherence under the current TB control program. Heavy financial burdens, lack of social support, adverse drug reactions and personal factors are associated with non-adherence. Direct observation and regular home visits by health workers appear to reduce the risk of non-adherence. More patient-centered interventions and greater attention to structural barriers are needed to improve treatment adherence

    Networked Non-fragile H∞ Control for Lipschitz Nonlinear System with Quantization and Packet Dropout in Both Feedback and Forward Channels

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    The networked non-fragile H∞ control problem for Lipschitz nonlinear system with quantization and packet dropout in both feedback and forward channels is investigated in this paper. The sensor measurement and controller output are quantized by logarithmic quantizers before transmitted over the network. The packet transmissions in the communication channels from the sensor to the controller and from the controller to the actuator are modeled as Markov chains respectively. Based on the Lyapunov functional approach, the networked non-fragile H∞ controller is designed to stabilize the Lipschitz nonlinear system and achieve the prescribed H∞ performance. Finally a numerical example is provided to illustrate the effectiveness of the proposed method

    An overview of phosphorescent metallomesogens based on platinum and iridium

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    Metal atoms with excellent magnetic, electrical and optical properties that are integrated into liquid crystal molecules-metallomesogens-have attracted much attention from chemists, physicists and engineers and many materials based on e.g. Ag, Pt, Pd, Ir, Ni, Cu and lanthanide ions have been reported. Though several reviews and books have been published on metallomesogens, few refer to their photophysical properties. Additionally, metallomesogens with good emission properties in solution or in neat film are still scarce. Owing to the 100% theoretical internal quantum efficiency, phosphorescent liquid-crystalline materials were developed recently. Here, a brief overview of recent research on such materials based on platinum and iridium complexes including their molecular design and structure-property relationships is reported. It is hoped that this review will stimulate further development of luminescent metallomesogens
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